Table 1.

Optimization of the reaction conditions for preparation of 2-amino-4-(4-chlorophenyl)-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile.

entry	solvent	temp. (°C)	catalyst (mg)	yielda (%)
1	EtOH	room temperature	—	Trace
2	EtOH	reflux	—	Trace
3	H2O	room temperature	—	Trace
4	H2O	reflux	—	Trace
5	EtOH	room temperature	20	65
6	EtOH	room temperature	30	96b
7	EtOH	room temperature	40	96
8	EtOH	reflux	30	90
9	H2O	room temperature	30	trace
10	CH3CN	room temperature	30	89
11	CH3CN	reflux	30	91

^aIsolated yield for product 4a, via coupling reaction between malononitrile (1.1 mmol) and 4-chlorobenzaldehyde (1.0 mmol), dimedone (1.0 mmol), in the presence of CuFe₂O₄@starch (30 mg) as a catalyst and ethanol as a solvent at room temperature.

^bOptimum conditions.